<template>
    <div class="search-form">

        <!-- 头部tab切换 -->
        <el-row type="flex" class="search-tab">
            <span v-for="(item, index) in tabs" :key="index"
            @click="handleSearchTab(item, index)"
            :class="{active: index === currentTab}">
                <i :class="item.icon"></i>{{item.name}}
            </span>
        </el-row>

        <el-form class="search-form-content" ref="form" label-width="80px">
            <el-form-item label="出发城市">
                <!-- fetch-suggestions 返回输入建议的方法 -->
                <!-- select 点击选中建议项时触发 -->
                <el-autocomplete
                :fetch-suggestions="queryDepartSearch"
                placeholder="请搜索出发城市"
                @select="handleDepartSelect"
                class="el-autocomplete"
                v-model="form.departCity"
                ></el-autocomplete>
            </el-form-item>
            <el-form-item label="到达城市">
                <el-autocomplete
                :fetch-suggestions="queryDestSearch"
                placeholder="请搜索到达城市"
                @select="handleDestSelect"
                class="el-autocomplete"
                v-model="form.destCity"
                ></el-autocomplete>
            </el-form-item>
            <el-form-item label="出发时间">
                <!-- change 用户确认选择日期时触发 -->
                <el-date-picker type="date" 
                placeholder="请选择日期" 
                style="width: 100%;"
                @change="handleDate"
                v-model="form.departDate"
                >
                </el-date-picker>
            </el-form-item>
            <el-form-item label="">
                <el-button style="width:100%;" 
                type="primary" 
                icon="el-icon-search"
                @click="handleSubmit">
                    搜索
                </el-button>
            </el-form-item>
            <div class="reverse">
                <span @click="handleReverse">换</span>
            </div>
        </el-form>  
      </div>
</template>

<script>
import moment from "moment";

export default {
    data(){
        return {
            tabs: [
                {icon: "iconfont icondancheng", name: "单程"},
                {icon: "iconfont iconshuangxiang", name: "往返"}
            ],
            currentTab: 0,
            // 表单提交参数
            form: {
                departCity: "", // 出发城市
                departCode: "", // 出发城市代码
                destCity: "",  // 到达城市
                destCode: "",  // 到达城市代码
                departDate: "", // 日期字符串
            },
        }
    },
    methods: {
        // tab切换时触发
        handleSearchTab(item, index){
          if(index === 1){
              this.$confirm("系统升级中，往返功能火热开放中！", '提示', {
                  confirmButtonText: '确定',
                  showCancelButton: false,
                  type: 'warning'
              })
          }
        },
        
        // 出发城市输入框获得焦点时触发
        // value 是选中的值，cb是回调函数，接收要展示的列表
        async queryDepartSearch(value, cb){
            const arr =  await this.querySearchAsync(value)
            if(arr.length > 0){
                // 不在下拉列表中选择，则默认选择第一项
                this.form.departCity = arr[0].value;
                this.form.departCode = arr[0].sort;
            }
            cb(arr)
        },

        // 目标城市输入框获得焦点时触发
        // value 是选中的值，cb是回调函数，接收要展示的列表
        async queryDestSearch(value, cb){
            const arr =  await this.querySearchAsync(value)
            if(arr.length > 0){
                // 不在下拉列表中选择，则默认选择第一项
                this.form.destCity = arr[0].value;
                this.form.destCode = arr[0].sort;
            }
            cb(arr)
        },

        // 查询城市接口的方法，返回promise
        // queryString是查询关键字
        querySearchAsync(queryString) {
            return new Promise((resolve, reject) => {
                // 如果关键字是空，则直接返回
                if(!queryString){
                    return resolve([]);
                }

                this.$axios({
                    url: `/airs/city`,
                    params: {
                        name: queryString
                    }
                }).then(res => {
                    const {data} = res.data;

                    // 下拉提示列表必须要有value字段
                    const arr = data.map(v => {
                        return {
                            ...v,
                            value: v.name.replace("市", "")
                        }
                    });
                    resolve(arr);
                });
            });
        },
       
        // 出发城市下拉选择时触发
        // item代表当前选中项
        handleDepartSelect(item) {
            this.form.departCity = item.value;
            this.form.departCode = item.sort;
        },

        // 目标城市下拉选择时触发
        // item代表当前选中项
        handleDestSelect(item) {
            this.form.destCity = item.value;
            this.form.destCode = item.sort;
        },

        // 确认选择日期时触发
        handleDate(value){
            this.form.departDate = moment(value).format("YYYY-MM-DD");
        },

        // 出发和目标城市切换时触发
        handleReverse(){
            const { departCity, departCode, destCity, destCode} = this.form;
            this.form.departCity = destCity;
            this.form.destCity = departCity;
            this.form.departCode = destCode;
            this.form.destCode = departCode;
        },

        // 提交表单时触发
        handleSubmit(){
          console.log(this.form);
            // 表单验证数据
            const rules = {
                depart: {
                    value: this.form.departCity, 
                    message: "请选择出发城市"
                },
                dest: {
                    value: this.form.destCity, 
                    message: "请选择到达城市"
                },
                departDate: {
                    value: this.form.departDate, 
                    message: "请选择出发时间"
                },
            }

            let valid = true; // 表单验证结果

            Object.keys(rules).forEach(v => {
                // 只要有一个结果不通过，就停止循环
                if(!valid) return;
                const item = rules[v];

                // 数据字段为空
                if(!item.value){
                    valid = false;

                    this.$confirm(item.message, '提示', {
                        confirmButtonText: '确定',
                        showCancelButton: false,
                        type: 'warning'
                    })
                }
            });

            // 不通过验证，不需要往下执行
            if(!valid) return;

            // 添加到本地存储
            const airs = JSON.parse(localStorage.getItem('airs') || `[]`);
            airs.push(this.form);
            localStorage.setItem("airs", JSON.stringify(airs));

            this.$router.push({
                path: "/air/flights",
                query: this.form
            })
        }
    },
    mounted() {
       
    }
}
</script>

<style scoped lang="less">
.search-form{
    border:1px #ddd solid;
    border-top:none;
    width:360px;
    height:350px;
    box-sizing: border-box;
}

.search-tab{
  span{
    display: block;
    flex:1;
    text-align: center;
    height:48px;
    line-height: 42px;
    box-sizing: border-box;
    border-top:3px #eee solid;
    background:#eee;
  }

  .active{
    border-top-color: orange;
    background:#fff;
  }

  i{
    margin-right:5px;
    font-size: 18px;

    &:first-child{
      font-size:16px;
    }
  }
}

.search-form-content{
  padding:15px 50px 15px 15px;
  position: relative;

  .el-autocomplete{
    width: 100%;
  }
}

.reverse{
  position:absolute;
  top: 35px;
  right:15px;

  &:after,&:before{
      display: block;
      content: "";
      position: absolute;
      left:-35px;
      width:25px;
      height:1px;
      background:#ccc;
  }

  &:after{
      top:0;
    }

    &:before{
      top:60px;
    }

  span{
    display: block;
    position:absolute;
    top: 20px;
    right:0;
    font-size:12px;
    background: #999;
    color:#fff;
    width:20px;
    height:20px;
    line-height: 18px;
    text-align: center;
    border-radius: 2px;
    cursor: pointer;

    &:after,&:before{
      display: block;
      content: "";
      position: absolute;
      left:10px;
      width:1px;
      height:20px;
      background:#ccc;
    }

    &:after{
      top:-20px;
    }

    &:before{
      top:20px;
    }
  }
}
</style>
